1. Field of the Invention
The present invention relates to sanitary towels for physiological liquids, with high absorbency, provided with a reduced surface expansion of the liquid absorbed through capillarity thanks to the particular manufacture of the surface layer (topsheet) in cotton or similar absorbent materials in natural fibres.
2. Description of the Related Art
Sanitary towels in cotton are more breathable with respect to conventional sanitary towels made with synthetic materials, and therefore generally more comfortable. Moreover these sanitary towels in cotton are suitable for all those who exhibit dermatological problems in contact with synthetic materials.
The sanitary towels in cotton currently present on the market are formed by a thin porous surface layer, in perforated and non-perforated nonwoven cotton, also known as topsheet, which has a function of covering with the sole purpose of forming a hypoallergenic contact layer. Below this topsheet an intermediate absorbent/filtering layer in cotton or in airlaid of cellulose fibres, with greater thickness, is positioned, which forms the core thereof, and a base polymeric film as support, also having the function of providing a surface on which to apply the adhesive strips for the attachment of said sanitary towel to the panty.
These sanitary towels can also be provided with so-called “wings”, also adhesive, which ensure an even better attachment of the sanitary towel to the panty. These wings are formed by the topsheet layer supported by the aforementioned polymeric film without any intermediate absorbent layer.
To date this topsheet is obtained from cotton fibres, in the form of a pad, which is subsequently subjected to hydroentangling or water needling (spunlace), thus forming a layer of cotton where the fibres are bound one to the other.
The spunlace technology binds the fibres using jets of water exiting from a jet strip of nozzles at high pressure, in general 60-80 bars, appropriately distanced, for example by 0.8 mm, with a diameter of approximately 0.08 mm. Said jets of water pass through the fibrous pad, binding one to the other the fibres below the high-pressure jets, and the nonwoven obtained in this way is resistant and at the same time soft, with grams per square meter varying generally from 20 to 60 g/m2.
Since cotton is notoriously an absorbent material with high capillarity, this type of sanitary towel suffers the disadvantage of exhibiting a high expansion of the liquid which traverses it with the consequent disadvantage of having a widening of the stain of liquid as far as the wings, soiling them.